The present invention relates generally to magnetic tape cassettes of the type used for electromagnetically recording digital signals on magnetic tape and, more particularly, to an improved protective cover resiliently mounted to a front side of the tape cassette for covering a tape access opening at the front side of the cassette for protecting the magnetic tape from contaminants which may enter the tape cassette and compromise tape performance.
Magnetic tape cassettes designed mainly for the recording of analog signals onto magnetic tape are well known. Such tape cassettes are inserted into conventional recording/playback apparatus, such as a cassette tape recorder having a magnetic head which reads the analog signals and converts the same into sound and/or video output signals. On the other hand, floppy discs have been used for recording digital signals. The floppy discs are contained within housings provided with openings by which the floppy discs are accessed by the magnetic head.
However, problems exist in the use of floppy discs. For example, since a shutter which covers the access opening of the floppy disc housing when it is not in use does not possess a locking mechanism, an operator may inadvertently touch the magnetic surface of the floppy disc due to carelessness or inexperience or even may touch the magnetic surface intentionally, thereby leaving fingerprints on the recording surface. The fingerprints may have oil, grease and water deposits which will damage the disc. Moreover, dust, dirt or other contaminants may reach the magnetic surface of the floppy disc through the access opening which will also cause serious problems. It is also well known that the highly flexible nature of the floppy disc requires the operator to handle the same with utmost care.
In an attempt to resolve the problems inherent in the recording and playback of digital signals, a magnetic tape cassette has been proposed for recording digital signals on magnetic tape. The cassette generally comprises a rectangular housing having a tape access opening in its front wall. A pair of reels are rotatably mounted in the housing on which magnetic tape is wound for travel from one reel to the other. The tape is guided in its travel past the access opening in the cassette housing during recording and playback. The cassette also includes a protective cover which covers the run of magnetic tape exposed at the access opening in the front side of the housing when the cassette is not in use to prevent contaminants from entering the opening and adhering to the magnetic tape. The cover is pivotally mounted to the cassette housing for movement between the above-described tape-covering position to an in-use position wherein the cover is pivoted about 90.degree. from its tape-covering position when the cassette is inserted into a slot of the cassette recording/playback apparatus.
Stop projections extend forwardly from the top and bottom walls of the cassette housing between which the protective cover is situated when in its tape-covering position to prevent the cover from inadvertently pivoting to its in-use position when the cassette is not in use.
However, the conventional construction of the cassette described above has the drawback that the front portion of the protective cover, which has a rectangular cross-section, normally projects forwardly beyond the end surfaces of the forwardly extending stop projections when the cover is in the tape-covering position and inadvertent engagement of the exposed top or bottom surface of the front portion of the cover during handling can cause undesired pivoting of the cover to its in-use position to expose the magnetic tape to contaminants.